EP0670951B1

EP0670951B1 - Method for detecting relative position of bores

Info

Publication number: EP0670951B1
Application number: EP94901918A
Authority: EP
Inventors: Matteo Vianini
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-12-04
Filing date: 1993-11-30
Publication date: 1997-02-19
Anticipated expiration: 2013-11-30
Also published as: ITMI922777A1; ES2100036T3; EP0670951A1; WO1994013931A1; ITMI922777A0; IT1256462B

Abstract

The present invention refers to a device for detecting distance and orientation of a second bore (22) as regards a first reference bore (21) and a method for detecting and for intersecting said two bores. The device comprises first emission means (23) of an electromagnetic field introduced in said first bore (21) and second means (24) of reception of said electromagnetic field in said second bore (22). A suitable application of this technique is in the field of stone cutting, e.g. of marble or granite cutting.

Description

FIELD OF THE INVENTION

The present invention refers to a device for detecting distance and orientation of a second bore as regards a first reference bore and a new method for detecting and for intersecting said two bores. A suitable application field of the instant invention is in the quarries, wherein a direct cutting from the stone mass is carried out by means of a diamond wire or by means of a helical wire, i.e. when it is necessary to drill two intersecting bores and to introduce the cutting wire into the bores, the wire being rotated by means of a cutting machinery.

PRIOR ART

In the art of stone cutting in quarries, a particular technique is adopted consisting of boring into the rock mass two intersecting bores. The cutting machinery rotates and pulls a loop formed by a diamond wire, or a helical one, which enters the first bore and goes out through the second one. The cutting machinery essentially consists of an electric engine (usually of around 50 HP power) mounted on a rail, having a pulley which rotates the stone-cutting wire. In the case of cutting by means of a diamond wire, the cut is produced by the friction of the diamond particles on the stone surface. The wire is not only rotated by the cutting machinery, but it is at the same time pulled by said machinery which moves along the rail.
Although a laser system is sometimes used in order to previously point two bits, it is usually very difficult to drill the second bore so that it intersects the first one after only few attempts. After the drilling of the first bore the user must make several attempts before succeding in intersecting the two bores. Accordingly, the use of such a system implies a large waste of materials (bits, lubricant etc.), electrical energy and specialized manpower.
American patent US-A-4,646,277 (J.E. Bridges et al.) describes a control system including an axial electromagnetic source for generating an axial alternating magnetic field directed along an axial source axis; a sensing assembly remote from the source means includes first and second pickup coils for sensing the alternating magnetic field. The outputs of the sensing coils are used to determine the direction of the lines of magnetic flux at the sensing assembly, and indicate the attitude of the source relative to the sensing assembly. This permits guiding of the boring tool by control signals sent to this tool. In other words, this invention is directed to a control system for controlling the direction and the rate of rotation of the boring tool about its axis. The invention has particular application in the installation of conduit and pipes by various utilities, such as gas, telephone and electric utilities. American patent US-A-4,791,373 (A.F. Kuckes) describes a method of locating, from a relief well, a target borehole of a deep well. A homing tool incorporating a magnetic field sensor having its axis of maximum sensitivity parallel to the axis of the relief well detects an A.C. magnetic field produced by alternating current in the target borehole to provide the data required for directing further drilling of the relief well.
However, both documents do not solve the problem stated in the present invention, i.e. the detection of the distance of two bores in order to allow, after some attempts, the intersection of said two bores. Furthermore, they require sophisticated electronics to operate with the sensing assembly.

SUMMARY OF THE INVENTION

For the above mentioned reasons the users working in this particular field require a simple device and an easy method which allow them to know the exact position and orientation of two bores in order to intersect them at a point.
Object of the present invention is a device for detecting distance and orientation of a second bore as regards a first reference bore and a new method for detecting distance and orientation of two bores and for intersecting said two bores at a point. Although expressly thought to be used for the stone cutting, e.g. marble or granite rocks, the device and the method objects of the present invention can be used when it is required to know the exact position of a bore with regard to another and/or when the intersection of the two bores is required.
The invention refers to a device for detecting distance and orientation of a second bore as regards a first one, and to a method for detecting and/or for intersecting said two bores characterized by the fact that said device comprises a first coil which produces an electromagnetic field and which is introduced in the first bore and a second coil receiving said electromagnetic field which is introduced in the second bore. After the drilling of two bores for a first attempt, their reciprocal distance and orientation is measured by means of the device object of the present invention. Starting from the data collected in this first attempt a second attempt is made, and so on, till succeeding in intersecting the two bores. This technique is suitable for stone cutting, e.g. marble or granite rock, which does not affect the electromagnetical field produced by the emitting coil. In order to carry out the stone cutting, the cutting wire must be introduced into the two intersecting bores, said wire being rotated by a cutting machinery.

LIST OF FIGURES

Figure 1 represents schematically a cutting machinery of a quarry.
Figure 2 represents a first embodiment of the device object of the present invention, which has only a theoretical meaning.
Figure 3 represents a second possible embodiment of the device object of the present invention.
Figure 4 represents a third possible embodiment of the device object of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

For reasons of clarity Figure 1 schematically represents the cutting machinery 13 performing a stone cutting in a quarry. It essentially consists of an electric engine 14 having normally a power of 50 HP mounted on a trolly 15 sliding on a rail 16. The electric engine 14 rotates a pulley 17 which in its turn rotates the helical or diamond cutting wire 18; this latter passes through the bores 11 and 12, previously drilled in the rock mass 20 and which intersect at point 19. At the same time, during the rotation of the pulley 17, the trolley 15 withdraws. When a diamond wire is used, the diamond particles present on the wire 18 rub the rock, thus taking away the stone particles which evacuate through the bores 11, 12.
Therefore, succeeding in intesecting the two bores 11 and 12 at point 19 after few attempts is capital to this kind of cutting.
By means of the device and of the method objects of the present invention it is possible to limit the mumber of attempts in order to intersect the bores 11 and 12 at point 19.
Figure 2 represents a first easy embodiment of the device object of the present invention. This embodiment has only a theoretical meaning, not allowing the detection or the orientation (on the right or on the left side) of the second bore as regards the first one.
The device object of the present invention comprises :

a) a first coil 23 (having the two tips connected with an alternate current generator) which produces a magnetic field $\vec{B}$
, said first coil being introduced into the first bore 21; and
b) a second coil 24 introduced into the second bore 22, whose two tips are linked with a tension or current detector (not shown in the figure), which thanks to suitable graduated scales allows the direct detection of the distance D between two bores 21 and 22 with a certain degree of approximation.

Although in Figure 2 the coils 23 and 24 are represented with the central axes perpendicular respectively to the bores 21 and 22, experimental results having the same degree of approximation can be possibly obtained if the central axes of the two coils 23 and 24 are parallel to the central axes of said bores 21 and 22.
By representing on a Cartesian plane the distance D between the two bores related to the magnetic field flux $\vec{B}$
(or the current or the voltage drop between the two tips of the second coil 24) it is possible to obtain a curve which asymptotically approaches the Cartesian axes and which gives the value of the distance between the two bores related to the current or the tension drop detected by the detector (not shown in the figure) linked with the tips of the second coil 24.
As already mentioned, the embodiment represented in Figure 2 has only a theoretical meaning because it permits the detection of the distance D but does not provide any information about the orientation of the second bore 22 with reference to the first one 21, i.e. the user does not know whether the bore 22 is on the right side or on the left side of the bore 21.
In order to determinate not only the distance D between the two bores obtained with the N attempt, but also the orientation (whether the second bore is on the right side or on the left side of the first bore), thus obtaining both extent and direction of the displacement to be carried out in the (N+1) attempt bore, the Applicant conceived the embodiments shown in the following figures, which have a merely illustrative meaning, not limitative of the present invention.
Figure 3 shows a second embodiment of the device object of the present invention. The first coil 33 producing the magnetic field is coiled around a L-shaped soft iron core mounted on a stick-shaped stiff element 36. Owing to the L-shaped core an oriented magnetic field B is generated. In the bore 32 there is a second coil 34 linked with a measuring instrument 35 (e.g. an Amperometer or a Voltmeter) having graduated scales which give directely the value of the distance D. In case the bore 32 is on the right side of the bore 31, as in Figure 3, when the coil 33 is directed towards the coil 34 the measuring instrument 35 marks a high value (Figure 3 A), whereas when it is directed towards the opposite direction (Figure 3 B) it marks a lower value. It would be the contrary in case the bore 32 were on the left side of the bore 31. In this way the user not only collects information about the value of the distance D between the two bores, but he also knows whether the second bore is on the right side or on the left side of the first bore. He can so calculate both extent and direction of the displacement in order to carry out the following bore. Normally, few attempts are enough to intersect the two bores 31 and 32.
In order to know whether the coil 33 is oriented towards the coil 34 or towards the opposite direction, an indicator 37 can be foreseen on the stiff means 36. It is placed outside the bore 31 and is clearly visible.
Figure 4 shows another system to determinate not only the value of the distance between the two bores, but also whether the second bore is on the right side or on the left side of the first one (orientation).
Figure 4 represents a third embodiment of the device object of the present invention; it essentially consists of a coil 43 which is lowered into the bore 41 and generates a magnetic field detected by two coils 44 and 45 placed in the bore 42. If the bore 42 is on the right side of the bore 41 the measurement instrument 46 linked with the coil 44 indicates a higher value than the value marked on the measuring instrument 47 linked with the coil 45. The contrary happens if the bore 46 is on the left side of the bore 41.
Remaining in the scope of the present invention, the skilled man can provide all the technical expedients in order to obtain reliable data on the exact position of the second bore with regard to the first one. In particular, amplifiers, filters and any electronic device can be provided in order to improve the quality of the outgoing signal and have reliable indications on the distance and on the orientation of a bore as regards the other one.
For pointing and drilling of two bores for the first attempt the user can also use a traditional pointing system, e.g. a laser system; afterwards he measures by means of the device object of the present invention distance and orientation (whether on the right side or on the left side) of the second bore as regards the first one; after this operation the user carries out another bore displaced of a D distance previously measured, and so on until the two bores intersect at a point. The user passes the cutting wire through the two bores in order to cut the rock by means of a cutting machinery.
The method object of the present invention is characterized in that:

a) a first attempt is made in order to intersect the first bore with the second one by means of any pointing system;
b) first means of emission of the electromagnetic field are introduced in the first bore;
c) second means for receiving the electromagnetic field are introduced into the second bore;
d) the second receiving means detect the distance D and the orientation of the second bore with regard to the first one;
e) a second bore is further carried out on the base of the data collected at point (d);
f) the operations effectuated at points (d) and (e) are repeated N times until succeeding in intersecting said two bores.

Claims

A device for detecting the distance and the orientation of a second bore (22; 32; 42) as regards a first one (21; 31; 41), characterized in the fact that it comprises at least one first coil (23; 33; 43) as emission means of an orientated electromagnetic field, said at least one first coil (23; 33; 43) being introduced into said first bore (21; 31; 41) already drilled and at least one second coil (24; 34; 44, 45) as detection means of said electromagnetic field, said at least one second coil (24; 34; 44, 45) being introduced into said second bore (22; 32; 42) also already drilled.
A device according to claim 1, characterized in that said first coil (33) is coiled around a L-shaped core.
A device according to claim 1, characterized in that said detection means consists of two coils (44, 45) connected to at least two different measuring instruments (46, 47).
A device according to claim 1, characterized in that at least a second coil (24; 34; 44, 45) is connected to at least one measuring instrument (35; 46, 47) and in that on said at least one measuring instrument there is at least a scale which gives directly the value of the distance D between said second bore (22; 32; 42) and said first bore (21; 31; 41).
A device according to claim 1, characterized in that said at least one first coil (23; 33; 43) and said at least one second coil (24; 34; 44, 45) have the central axes transversal to the central axes of the respective bores (21; 31; 41) (22; 32; 42).
A device according to claim 1, characterized in that said at least one first coil (23; 33; 43) and said at least one second coil (24; 34; 44, 45) have the central axes parallel to the central axes of the respective bores (21; 31; 41) (22; 32; 42).
A device according to claims 1-6, characterized in that it is used in a stone quarry in order to introduce a loop formed by a diamond cutting wire into said two bores.
Method for detecting the distance and the orientation of a second bore as regards a first reference bore and for the intersection of said two bores characterized in that :
a) a first attempt is made in order to intersect the first bore with the second one by means of any pointing system;

b) first means of emission of the electromagnetic field is introduced in the first bore;

c) second means for receiving the electromagnetic field is introduced into the second bore;

d) the second receiving means detect the distance D and the orientation of the second bore with regard to the first one;

e) a second bore is further carried out on the basis of the data collected at point (d);

f) the operations effectuated at points (d) and (e) are repeated N times until succeeding in intersecting said two bores.
A method according to claim 8, characterized by the use of a device according to claims 1-6.
A method according to claim 8, characterized in that it is used for the stone cutting in a quarry.